WO2012065870A1

WO2012065870A1 - Discharge lamp with an outer bulb surrounded by a wire mesh as explosion protection

Info

Publication number: WO2012065870A1
Application number: PCT/EP2011/069506
Authority: WO
Inventors: Johannes Buttstaedt; Stefan Dunkel; Andreas Genz; Maik Hegewald
Original assignee: Osram Ag
Priority date: 2010-11-17
Filing date: 2011-11-07
Publication date: 2012-05-24
Also published as: CN103210469A; US8786187B2; US20130285543A1; DE102010044045A1; DE112011103804A5; CN103210469B

Abstract

High-pressure discharge lamp with a discharge vessel sealed in vacuum-tight fashion, said discharge vessel being surrounded by an outer bulb. The outer bulb is closely surrounded by a wire mesh as explosion protection. The wire mesh is characterized by the wire diameter D, the mesh width B and the mesh length L of the mesh, the ratio L/D being in the range from 25 to 60, boundary values inclusive.

Description

DISCHARGE LAMP WITH ONE OF A WIRE NETWORK SURROUNDED AS SPACE PROTECTION

EXTERNAL PISTON

Technical area

The invention relates to a discharge lamp according to the preamble of claim 1. These are in particular 5 metal halide lamps with outer bulb.

State of the art

From DE 43 17 252 and EP 306 269 a lamp is known in which the discharge vessel by a Drahtge ^¬ braids or wire mesh is protected against Platzer. However Derar- 10 term Grids are problematic because of the risk ^¬ kos of sodium output and the high production costs due to the complicated assembly.

Presentation of the invention

It is an object of the present invention to provide a lamp according to the preamble of claim 1, which allows a reliable Platzerschutz at low additional costs. A further task is to avoid as much as possible the escape of Na in the case of a Na-containing filling.

This object is solved by the characterizing features of claim 1. Particularly advantageous ^{Ausgestaltun ¬} conditions can be found in the dependent claims.

The lamp according to the invention is suitable for operation in open luminaires, since it has a wire mesh as a reliable Platzerschutz.

The proposed bursting protection is suitable for high-pressure discharge lamps, in particular with metal halide filler. development. Usual wattages are 50 to 400 W. The Platzerschutz is suitable for all fillings, but develops special advantages in Na-containing fillings. Usually, sodium is introduced as NaJ. If this compound decomposes in the discharge arc, the Na ion can penetrate the hot quartz wall when a corresponding electric field is applied. This mechanism is prevented by the wire net.

The discharge vessel can be closed on one side or preferably on both sides. It is made of quartz glass or Kera ^¬ mik as A1203.

The luminous means in the interior of the discharge vessel is a discharge arc between two electrodes. It is electrically connected to feedthroughs leading to it.

According to the invention, a construction is proposed in which the discharge vessel is enclosed by an outer bulb. In particular, it is firmly merged with this. On a central cylindrical part of the outer bulb, a wire mesh is applied, which is designed so that it rests firmly on the outer bulb without further holding elements and does not slip. This construction is in particular with a frame in an over-piston, which carries the base and the power supply lines. The wire mesh is characterized by the wire diameter D, the mesh width B and the mesh length L. The following conditions apply in particular:

The ratio L / D is preferably between 25 and 60. Furthermore, the ratio NF / P between the net surface covered by the drainage network in mm ² and that of FIG Lamp power P m W is preferably between 10 and 35. The ratio Z / L of the length of the cylindrical portion Z of the outer bulb to L is preferably between 3 and 12. The ratio U / B from the circumference U of the cylindrical portion of the outer bulb to B is preferred between 5 and 20. In this way, not only is optimum protection achieved, but at the same time shadowing by the wire net minimized.

Overall, thus ensuring a Platzerschutzes to the lowest possible manufacturing costs with a possible low loss of luminous flux compared to a lamp without Platzerschutz ensured.

In a particularly advantageous embodiment, the outer bulb tapers at the ends of its cylindrical part. Then it is possible to apply the Drahtnezt without any support on the outer bulb.

Advantageously, the wire net has at its two ends a reduced mesh size with respect to its middle part (seen in the axial direction). This creates so-called cuffs at the ends, which is a kind of gathering, so that the wire mesh adheres well to the outer bulb. The cuffs act in particular with the tapered end to a particularly reliable holder together.

Since this can be dispensed with holding elements, the well-known risk of sodium leakage from the discharge vessel is significantly reduced.

The self-holding of the net reduced

Manufacturing costs for attaching the network clearly. The orientation of the mesh is usually parallel to the axis, but this is not absolutely necessary. Instead of rectangular mesh, for example, also karoförmige mesh can be used. In such cases, L means the largest Längsabemssung a mesh, seen axially parallel, and B with the largest dimension of a mesh transverse to the longitudinal axis.

Essential features of the invention in the form of a nume ^¬ tured list are: 1. High-pressure discharge lamp comprising a vacuum-tight abge ^¬ closed discharge vessel which defines a longitudinal axis (A) which contains an ionizable filling and two electrodes, and that is enclosed by an outer bulb, wherein the outer bulb has a cylindrical middle part, characterized in that at least the cylindrical middle part is closely surrounded by a wire net as a protection against bursting, wherein the wire net is characterized by the wire diameter D and the mesh length L of the net, and wherein the ratio L / D in the range 25 to 60, edge ^¬ values included, is located.

2. Lamp according to claim 1, characterized in that in the region of the middle part, the ratio between the regular network area NF in mm ² and the lamp power P is between 10 and 35, including boundary values.

3. Lamp according to claim 1, characterized in that the ratio between the length Z of the cylindri ^¬ 's middle part and the value L in the range 3 to 12, including boundary values. 4. Lamp according to claim 1, characterized in that the ratio between the circumference U of the cylindrical central portion and the mesh width B of the network is between 5 and 20, including boundary values. 5. Lamp according to claim 1, characterized in that the discharge vessel contains metal halides, in particular ^¬ special sodium as the metal of the halide.

6. Lamp according to claim 1, characterized in that the wire mesh has at least one end region in which the length of the mesh LR is reduced relative to the main region, and preferably reduced by at least 30%, more preferably at least 50% reduced compared to the main region ,

7. Lamp according to claim 1, characterized in that the outer bulb is made of quartz glass.

8. Lamp according to claim 1, characterized in that the wire mesh rests directly on the outer bulb or a part thereof.

9. Lamp according to claim 6, characterized in that the outer bulb has at least one end which tapers relative to the central part.

10. Lamp according to claim 1, characterized in that the wire mesh is at least partially applied double-layered.

Brief description of the drawings

In the following the invention will be explained in more detail with reference to several embodiments. Show it: Figure 1 shows an embodiment of a metal halide lamp in side view;

Figure 2-4 further embodiments of a metal halide genidlampe in side view. Preferred embodiment of the invention

FIG. 1 shows the structure of a high-pressure discharge lamp 1 in a highly schematic manner. It has a discharge vessel 2 with two ends 12, which is housed in an outer bulb 3, which also has two ends 13, so that the outer bulb defines a longitudinal axis A. Both pistons are made of quartz glass, but the discharge vessel can also be made of ceramic such as A1203. The outer feeders 4 of the discharge vessel, the electrodes 7 in contact ^¬ In partners are, by the tapered ends 13 of the outer bulb through extended and outside with two frame wires 5 and 6 are connected. A short frame wire 5 leads to a first supply line of the base 9. A long frame wire 6, often called stirrup wire, leads to a second supply line of the base. Both supply lines are fixed in a circular base 10 which sits in ei ^¬ nem About plunger. 11 A wire mesh 22 extends here on the cylindrical central part of the outer bulb 3 and is uniformly structured.

The detail of FIG. 1 a shows the diameter D of the wire, in most cases it is a heat-resistant stainless steel wire, the length L of the individual stitch and the width B of the single stitch. Over the entire wire mesh these sizes are constant in this embodiment. For concrete networks, the following design rules are observed:

L / D is between 25 and 60. Furthermore, the ratio of the net area in mm ² to the lamp power in W is between 10 and 35. The ratio of the length LK of the cylindrical part of the outer bulb to L is between LK / L = 3 and LK / L = 12. The ratio of the circumference U of the cylindrical part of the outer bulb to B is between U / B = 5 and U / B = 20. Concrete embodiments are as follows:

Example 150W lamp:

Outer bulb length AKL = 50mm,

Outer bulb diameter 22 mm,

D = 0.11 mm; L = 6 mm;

Outer bulb length to L: AKL / L = 8,3

Extent to B: U / B = 17.2

Net area in mm ² to power P in W: NF: P = 23

L / D = 54.5

Luminous flux loss through the Platzerschutz 4%.

Embodiment 70W:

Outer bulb length AKL = 32 mm,

Outer bulb diameter 19 mm,

D = 0.11 mm; L = 6 mm;

Outer bulb length to L: AKL / L = 5.3

Extent to B: U / B = 14.9

Net area NF in mm ² to power P in W: NF / P = 25.4 L / D = 54.5

Luminous flux loss due to the burst protection 6%. Generally, according to Figure 2: The wire mesh 22 has an edge region 24 of axial length ZR, which at each end has a length of typically 5% to 15% of the total length Z of the cylindrical portion of the outer bulb. This edge area serves for better fixation of the wire net without further holding or clamping elements. This Randbe ^¬ rich 24 can complete in particular according to Figure 2 with the cylind ^¬ cal part of the outer bulb. According to Figure 3, it can easily survive. In a further exemplary embodiment according to FIG. 4, at least the edge region 24 or even the entire wire mesh can be turned over once, see FIG. 4a, where the two wires are slightly shifted relative to one another, numbered XI and X2.

In this edge region, the mesh length LR is reduced from L in all three embodiments. It is preferably L: LR = 1.5 to 5. The mesh width BR can, but need not, be reduced at the edge compared to B, it applies B: BR = 1 to 2.

FIG. 4 shows a particularly preferred exemplary embodiment of a high-pressure discharge lamp 1 with metal halide filling which contains halides of Na as filling. In this case, it is very advantageous that the outer bulb 3 has tapered ends 13. The wire mesh 22 is extended so far that it extends to a part of the end 13 of the outer bulb. In the end region 32 of the wire mesh, however, the mesh is narrowed so that it casts cuffs. The mesh length LR is significantly reduced compared to the value L at the middle part of the outer bulb. It is typical that the value for L of 50% the value is reduced in the central part 22 at the highest least, be ^¬ vorzugt is a value of 0.2L to 0,45L for LR. At a- Attitude of this rule provide the cuffs for a pronounced self-holding effect in the region of the tapered ends 13 of the outer bulb.

In principle, such a wire mesh is also applicable to other lamps. If necessary, the wire net may also have cuffs only at one end region. This preferably applies to an end region located at the top under operating conditions.

Claims

claims

1. A high-pressure discharge lamp comprising a vacuum-tight abge ^¬ closed discharge vessel which finiert a longitudinal axis (A) de ^¬ containing an ionizable filling and two electric ^¬, and that is enclosed by an outer bulb, the outer bulb has a cylindrical middle part, characterized in that at least the zy ^{¬-cylindrical} middle part is surrounded closely by a wire net as Platzerschutz, wherein the wire mesh by the wire diameter D and the loop length L of the network is characterized and wherein the ratio L / D ^¬ rich included 25 to 60, boundary values in be , lies.

2. Lamp according to claim 1, characterized in that in the region of the central part, the ratio between the re ^¬ gular network area NF and the lamp power P is between 10 and 35, including boundary values.

3. Lamp according to claim 1, characterized in that the ratio between the length Z of the cylindrical central part and the value L is in the range 3 to 12, border ^¬ values included.

4. Lamp according to claim 1, characterized in that the

Ratio between the circumference U of the cylindrical central portion and the mesh width B of the network is between 5 and 20, including boundary values.

5. Lamp according to claim 1, characterized in that the discharge vessel contains metal halides, in particular sodium as metal of the halide.

6. Lamp according to claim 1, characterized in that the wire mesh has at least one end region, in which the length of the mesh LR is reduced compared to the main region, and preferably reduced by at least 30%, more preferably reduced by at least 50% ge ^¬ compared the main area.

10. Lamp according to claim 1, characterized in that the wire mesh is at least partially double-layered ^¬ brought.